ABSTRACT The mission of the UCLA-Caltech MSTP is to educate and train outstanding physician-scientists. To fulfill this mission, our current goals are to 1) recruit exceptionally bright and accomplished students who exhibit unusual passion for scientific knowledge and a life-long commitment to research, medicine, service, and leadership; 2) help guide admitted students toward outstanding training environments that encourage individual thinking and provide tools for development into accomplished physician-scientists; 3) provide a comprehensive support system to meet trainees' needs; and 4) enhance physician-scientist diversity by playing an increasingly prominent role in guiding the career development of current and future students from under-represented ethnic groups and disadvantaged backgrounds through mentoring and outreach. To accomplish these major goals as effectively as possible, the UCLA-Caltech MSTP is led by two equal Co-Directors, four Associate Directors, and a strong administrative team, all of whom are deeply committed to the Program. The Program is structured for an average of eight years of combined research and clinical training. Our integrated problem-based medical school curriculum emphasizes flexibility and is particularly well suited for MSTP students because it provides increased time for independent scientific exploration and encourages trainees to pursue research projects that will advance current knowledge of disease etiology, diagnosis, and treatment. For Ph.D. training, students choose mentors affiliated with a broad array of UCLA and Caltech graduate programs, most frequently in genetics & genomics, immunology, cell & developmental biology, neuroscience, bioinformatics, bioengineering, or our newly instituted social sciences track. A recent milestone achievement of our Program was the recent 20th anniversary of the affiliation between UCLA and Caltech into a joint MSTP (1997) for the mutual benefit of these preeminent campuses and our trainees. A second remarkable celebratory achievement will be the upcoming centennial of UCLA becoming a UC campus (1919) and its amazing rise to a world-ranked institution in research, education, and service in under 100 years of existence. A prominent goal of UCLA?s Centennial Campaign is to raise $4 billion, one-third of which is earmarked for research. Despite a competitive funding climate, the UCLA- Caltech MSTP is in a period of substantial growth because of generous institutional support from the David Geffen School of Medicine at UCLA and from Caltech. This has permitted an increase in the size of the Program, with 107 current students. The MSTP benefits tremendously from substantial improvements and expansion in physical facilities and research capabilities at UCLA and Caltech, from the strong financial health of both universities, and from the recruitment of many outstanding new faculty members to our campuses.